Yet it is not as straightforward as that. In creating a garden we are interfering with nature by inventing an artificial landscape in which creatures and plants raised in the wild may not feel at home. We are invading their space and imposing our own vision on it.
That fundamental point is illustrated neatly by contrasting the two new model gardens opened recently at the Royal Horticultural Society's show garden at Wisley in Surrey. One is expressly conceived to provide a welcoming habitat for many kinds of wildlife; the other to accommodate the often conflicting demands of the human species, especially its young.
The Garden for Nature, designed with advice from the Royal Society for the Protection of Birds, was first seen at the Chelsea Flower Show in May. It has been designed by Hilde Wainstein, a 45-year-old mother of three who in 1993 enrolled as a mature student on Middlesex University's degree course in garden design. Last year she won a competition, sponsored by the makers of Bradstone garden paving, to design a garden for Chelsea. Naturally, the winning design had to feature the sponsor's products - but there was also an RSPB representative on the judging panel to ensure that the interests of birds were equally to the fore.
In a confined space, it is remarkable how many habitats for wildlife Mrs Wainstein has managed to include. "It wasn't at all easy," she told me. "I've made it so that every part of the garden is a living space for something. One aim was to have something in flower all the time so that the bees can collect nectar and pollen."
Starting from the front, there are two raised beds clad with Bradstone's artificial stone walling and filled with plants that like free-draining conditions, such as verbascum. The crevices between the stones provide habitats for the insects and small animals attracted to them, and so do the spaces in the paving at the front of the garden, filled with low-growing plants that spread between the stones. Behind the raised bed on the left of the paving is a "nectar border", where the plants have been selected for colour, perfume and length of flowering to appeal to bees. Most of the flowers are self-seeding, and if the seed heads are left on they provide birds with winter food and material for nest-building in spring.
At the back of the paving is a small pond and a waterfall. The sight and sound of water attract many birds, as well as dragonflies and other insects. On a raised level behind it is a damp meadow, harbouring flowers such as mallow and mimulus, which thrive in those conditions, with the grass kept long to attract small mammals.
Behind this is a bird-feeding table, with a spiky coil around its post to keep cats away. Further back is a lawn whose grass, in contrast to the damp meadow, is kept short - perfect for insects that breed on the ground. A pile of logs placed just in front of it will give shelter to hedgehogs and mice, and attract insects that feed on wood.
Beyond is a small woodland area and hedgerow. Here, shrubs such as holly and cotoneaster have been planted, so that birds will be able to enjoy a feast of winter berries. Many wild flowers have been introduced, including red clover, ragged robin, wild garlic, celandine and viper's bugloss. There are nesting boxes not just for birds but also for bats, which perform a useful service by eating midges.
At the insistence of the RSPB, every effort has been made to obtain plants from nurseries that do not use peat in their growing compost. For years the society has been campaigning against the extraction of peat from sites that provide habitats for rare birds.
In sharp contrast, the second of Wisley's new gardens is designed to meet the needs of a family with young children. It has been designed by John Battye, floral superintendent for the RHS, who said: "I've tried to include services a family would need, as well as making it pleasant to be in."
No bat boxes or water meadows here, then; but a climbing frame, rotary clothes' line, summer house, barbecue and dustbin area have been incorporated into the design, as well as a tough lawn for romping (thanks to its sponsor, Rolawn). Trellising is much in evidence, for Mr Battye hides the working areas behind what will, when the garden matures, be screens adorned with roses and other climbing plants.
The practical nature of the design extends to what is grown in the family garden. Vegetables mingle with flowers in the ornamental beds, where runner beans run up a wigwam structure, with white-flowered (Mergoles) and red- flowered (Royal Standard) varieties on alternate poles. Nearby, the dog- toothed leaves of a turnip show up well alongside pretty pink shrub roses, appropriately named Surrey.
"The old vegetable garden has gone out of style," Mr Battye declares. "People still want to grow some fresh vegetables for the family but they don't want to give up a whole chunk of their garden to do it in. If you choose varieties that look good you can grow them anywhere."
A dedicated herb garden, on the other hand, is the height of fashion. Mr Battye has placed one close to the patio, so that when the family eat and drink outdoors they will catch the fragrance of lavender, camomile, dill, rosemary, basil and mint, and will be able to snip fresh parsley to sprinkle on the vichyssoise.
Comparing the cost of the two new gardens gives the edge to the ecologically virtuous. Mrs Wainstein's budget was just pounds 10,000, while Mr Battye, with his expensive structural elements, splurged pounds 35,000 on his patch.
The attempt to strike a balance between the demands of garden users and those of the environment is being made on a much larger scale in the new plans for Wisley itself. The long and ambitious programme will not be completed until 2004 - the Society's bicentenary as well as the 100th anniversary of its acquisition of Wisley.
In the last three decades the annual number of visitors has tripled to more than 600,000. Now the facilities need to be upgraded to match the increase in numbers. A new entrance, visitor centre and cafe are planned, as well as a walled garden where Victorian techniques will be demonstrated.
The highlight of the scheme is a spectacular curved glasshouse with the roof glass designed in a pleated pattern, looking something like a section of an Elizabethan ruff. Visitors will walk through it on an undulating path, passing through various climatic zones.
Once these improvements are in place, Wisley may be able to accommodate a million visitors a year. Yet the underlying question is that suggested by the two new model gardens: as the number of human visitors increases, will the hundreds of species of wildlife find less and less to attract them?
! The RHS Garden at Wisley is signposted from the M25 (junction 10) and A30 north of Guildford. Open Mon-Sat, 10am-7pm, pounds 4.70 adults, pounds 2.75 children 6-16; free to RHS members and children under 6. RHS members only on Sundays